The list changed. Most hardening programs haven't.

Application security programs built around the OWASP Top 10:2021 are now running against an outdated map. The 2025 edition retired that list after four years, and the rewrite is substantial: Broken Access Control keeps the number one position it has held across every cycle since introduced, but Security Misconfiguration jumped from fifth to second place, now present in a meaningful share of tested applications, and Cryptographic Failures and Injection both dropped in rank as other categories proved more prevalent in the underlying data. Server-Side Request Forgery, previously its own standalone category, has been folded entirely into Broken Access Control, reflecting how the two are now routinely exploited together in cloud environments.

The second problem is the two categories that didn't exist in 2021 at all. Software Supply Chain Failures expands what used to be a narrower \"vulnerable components\" category into something far broader, covering compromises across the entire ecosystem of dependencies, build systems, and distribution infrastructure, and it was voted a top community concern in the survey behind the list. Mishandling of Exceptional Conditions is the other new entry, covering improper error handling, logic flaws, and fail-open behavior — a category with real, if underrepresented, presence in current testing data. Neither of these existed as a formal hardening target for most application security programs until this release.

The third problem is one most teams haven't internalized yet: OWASP explicitly rebuilt the 2025 list around root causes rather than symptoms. Where the 2021 list named \"Sensitive Data Exposure,\" a symptom, the 2025 list names \"Cryptographic Failures,\" the actual root cause behind it. Hardening programs still organized around the old symptom-level categories are structurally misaligned with how the current list, and increasingly how modern scanning and compliance tooling, actually categorizes risk.

We harden applications directly against the OWASP Top 10:2025 category structure, not the 2021 baseline still embedded in a lot of legacy tooling and training material. That means treating Broken Access Control (now absorbing SSRF) as the highest-priority category by default, hardening configuration management as a first-class discipline given Security Misconfiguration's jump to second place, and building explicit coverage for both new categories — supply chain integrity checks for Software Supply Chain Failures, and structured error handling and fail-safe design review for Mishandling of Exceptional Conditions.

For every category, we map to the specific CWEs OWASP has assigned under the 2025 structure rather than working from a generic checklist, since the new edition ties each category to a defined set of underlying weaknesses — from 5 CWEs in the newer, more narrowly scoped categories up to 40 in Broken Access Control — which lets remediation guidance stay precise to your actual language and framework rather than generically worded. And because the list itself is explicitly a root-cause reorganization, our hardening documentation and developer training are rebuilt around the same root-cause framing, so the language your team learns matches the language the list, your scanners, and your compliance mappings now actually use.